A fighter aircraft is a military aircraft designed primarily for attacking other aircraft. Compare with bomber. Fighters are comparatively small, fast, and highly manoeuverable, and have been fitted with increasingly sophisticated tracking and weapons systems to find and shoot down other aircraft.

At one time, just before the opening of World War II, there were two types of fighters. Smaller single-engine planes were used as interceptors and day fighters, sometimes referred to as pursuit, while larger twin-engine designs were used as heavy fighters. The later role proved to be unworkable, or at least not enough effort was put into them to remain useful. They then found themselves being converted to an ever-growing list of secondary roles, including strike fighters, bomber destroyers and night fighters, where their two engines gave them the increased payload needed to fill these roles.

As the performance of aircraft engines improved, notably with the jet engine in the 1960s, the need for different designs gradually disappeared. First the interceptor, bomber destroyer and night fighter designs merged into a single aircraft class. Later advances in targeting systems and the ever-increasing payloads meant that modern fighters can carry a load as large as the biggest WWII bombers, eliminating many of the bomber and attack aircraft roles as well. Today there are typically only two general fighter designs, smaller planes which make up the backbone of most air forces, and larger designs that operate at longer distances, sometimes referred to as interdictors[?].

Fighter aircraft developed during World War I, when they were tasked with hunting down enemy reconnaissance aircraft and balloons. Engine power was so scarce that they were barely able to lift themselves, but by the end of the war they had become one of the primary designs in the inventory.

By the time of World War II fighter aircraft were extremely important. Control of the sky, or air superiority, had become a vital part of military doctrine, notably in the case of the blitzkrieg. The Luftwaffe's inability to destroy the British fighter squadrons made the seaborne invasion of Britain infeasible. As engine power grew, existing designs were increasingly used in other roles, with aircraft like the Republic P-47 and Hawker Typhoon becoming celibrated attack aircraft.

Messerschmitt developed the first operational jet fighter, the Me 262, proving to be significantly faster than conventional propeller-driven aircraft. In general terms these were untouchable as long as the pilot used the speed advantage. They could simply fly away from defending fighters, or in the hands of a more competent pilot, they could run down opposing fighters so quickly they simply didn't have time to get out of the way of its guns. They were little used, partly due to German fuel shortages. Moreover, their speed advantage was significantly negated by Hitler's insistence that they be used primarily as fighter bombers. Nevertheless the plane clearly pointed to the end of the propeller engine for fighters. Great Britain soon followed with their Gloster Meteor, and by the end of the war almost all work on piston powered fighters had ended.

In the 1950s, jet-engined fighter planes capable of supersonic flight were developed. Power remained low, and the designs were dedicated to specific roles. Any particular air force might deploy three or four designs, day fighters, night fighters, attack planes, etc.

By the 1960s these distinctions had continued to erode. One of the classic "multi-role" aircraft is the McDonnell F-4 Phantom II, which was used in practically every role. By the 1970s this evolution was largely complete. Current developments include reducing the radar visibility of fighters, techniques known as stealth[?], as well as increased range at supersonic speeds and better manoeuverability.

French aviator Roland Garros became the first flying "ace" (a pilot who shoots down five or more enemy aircraft) when he affixed machine guns to his aircraft (Morane-Saulnier Type L) which fired through the propeller, although he used crude metal deflector plates (the bullets hit the propeller but were deflected aside) rather than interruptor gear[?]. Dutch aircraft designer Anthony Fokker developed the first interruptor for the machine gun, which prevents bullets from hitting the propeller of the aircraft.

Many of these fighters would do over 400 m.p.h. in level flight, and were fast enough in a dive that they started encountering the effects of getting too close to the speed of sound, occasionally even to the point of breaking up in flight. Dive brakes were developed late in WW II to minimize these problems and restore control to the pilots.

The first generation of production jet fighter planes had performance problems near sonic speed (similar to that of the latest piston engined fighters) until aeronautical engineer Richard Whitcomb discovered the "area rule" in 1952. Subsequent designs featured a "bottle-shaped" fuselage that improved performance. This would be an important distinction between early jet fighters (F-86, etc.) and later ones, like the F-5.